Liquid displacement pumps



Oct. 15, 1968 R. T. J. SKINNER LIQUID DISPLACEMENT PUMPS Filed June 8, 1966 United States Patent 3,405,644 LIQUID DISPLACEMENT PUMPS Robert Thomas John Skinner, Kenilworth, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England, a British company Filed June 8, 1966, Ser. No. 556,235 4 Claims. (Cl. 103-97) ABSTRACT OF THE DISCLOSURE A liquid displacement pump in which a bladed rotor is mounted within a cavity in a pump body having an inlet and outlet at angularly spaced positions around the rotor periphery. The body has a part-annular recess in the cavity wall extending around the periphery at least between the position of the inlet and that of the outlet. A spoiler is mounted within the body and is capable of movement into the cavity for preventing or reducing continuity of liquid flow between the inlet and outlet through the recess and the spaces between adjacent rotor blades.

This invention relates to liquid displacement pumps of the kind having a body, a bladed rotor within a cavity in the body, the body having an inlet and an outlet at angularly spaced positions around the periphery of the rotor, and a part-annular recess defined within the body in the wall ot the cavity extending around the periphery of the rotor at least between the position of the inlet and that of the outlet.

The object of this invention is to provide a pump of the kind specified in a convenient form.

In accordance with the present invention, a liquid displacement pump of the kind specified includes spoiler means capable of being introduced into the recess for preventing or reducing the continuity of flow of liquid between the inlet and the outlet through the part-annular recess and through the spaces between adjacent blades of the rotor.

The invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a cross-sectional view taken along the line II in FIGURE 2 of a pump constructed in accordance with this invention and FIGURE 2 is a cross-sectional view taken along the line II-II in FIGURE 1.

In the example shown, there is provided a pump which is particularly suitable for supplying liquid fuel to a gas turbine engine. The pump comprises a body defining a cylindrical cavity 11 within which is mounted a rotor denoted generally 12. The rotor 12 is connected to a shaft 13 which can be driven by the engine to which the pump is intended to supply fuel, in the direction indicated by the arrow 9.

The rotor 12 includes a hub 12a and fiat radial blades 12b and is of a size to sweep the whole of the cylindrical cavity 11 and one side wall has a pair of diametrically opposite inlets l4 and a similarly disposed pair of outlets 15, the inlets 14 and'outlets 15 being angularly spaced and being in communication with respective adaptors 16, 17 on the body 10. The inlets 14 and outlets 15 are disposed adjacent to the rotor periphery.

In the siie walls of the cavity 11 are formed respective pairs of semi-circular recesses 18 divided by a pair of fixed abutments 19, the ends of the recesses being respectively adjacent to the positions of the inlets 14 and t e outlets 15.

The recesses 18 are of U-shape in cross-section and their outside peripheral edges are approximately coincident with the cylindrical wall of the cavity 11, the widths of the recesses 18 in the radial direction being approximately one third of the radius of the rotor 12.

Mounted within the body 10 on spindles 20 are respective pairs of spoilers 21. Each spoiler is housed in a slot in the body 10 and has teeth 22 engaging with a gear 23 mounted upon a spindle 24. The spoilers are mounted in pairs upon the spindles 20 and the gears 23 are also mounted in pairs upon the spindles 24. The spindles 24 are interconnected by external links 25, 26, the latter link being connected to an appropriate operating mechanism (not shown). The spoilers 21 can be moved in unison by the link 26 from the positions shown in which they are completely housed in their respective slots, to the positions indicated in dotted lines 27 in which they partially impede entry of liquid being pumped, into the recesses 18.

In use, when the pump is as illustrated with the spoilers retracted into their slots, the rotation of the rotor 12 causes liquid to flow through the inlets 14, between the rotor blades 12b and into the recesses 18 and to the outlets 15. It is believed that there is a tendency for the liquid flowing between the inlets 14 and outlets 15 to follow a generally part-toroidal path through the spaces between the rotor blades 12b and the recesses 18. The insertion of the spoilers into the recesses 18 tends to prevent or reduce the continuity of the flow and thus has the efiect of reducing the outlet pressure and also the rate of flow through the pump.

In a modification, a single recess and a single inlet and an outlet are provided. With the arrangement described however, a pair of inlets 14 and a pair of outlets 15 tends to balance the loads exerted on the pump.

The invention is not to be confined to any strict conformity to the showings in the drawings but changes or modifications may be made thereto so long as such changes Or modification mark no material departure from the spirit and scope of the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A liquid displacement pump including a body having a cavity therein, a bladed rotor Within the cavity, said body having an inlet and an outlet at angularly spaced positions around the periphery of the bladed ro tor, said body being provided with a part-annular recess in the wall of the cavity extending around the periphery of the bladed rotor at least between the position of the inlet and that of the outlet, and spoiler means movably mounted within said body and capable of being introduced into the cavity for preventing or reducing the continuity of flow of liquid between the inlet and the outlet through the part-annular recess and through the spaces between adjacent blades of the rotor.

2. The liquid displacement pump as claimed in claim 1 in which the spoiler means comprises a spoiler arranged to be movable from a position wholly disposed within a slot provided in the body and a position in which the entry of liquid to the recess is restricted.

3. The liquid displacement pump as claimed in claim 1 in which there are two pairs of recesses at the sides of the rotor respectively with individual spoiler means being provided for the recesses respectively.

4. The liquid displacement pump as claimed in claim 3 in which the individual spoiler means are coupled together so as to be movable in unison.

References Cited UNITED STATES PATENTS 3,257,955 6/1966 Worst 103--97 3,259,072 7/1966 Carpenter 103-97 XR ROBERT M. WALKER, Primary Examiner. 

